How It Works

More than 40 countries have approved the use of radiation to help preserve nearly 40 different varieties of food. In agriculture, radiation has eradicated approximately 10 species of pest insects.

In the United States, the U.S. Food and Drug Administration has approved the use of irradiation for fruits, vegetables, pork, poultry, red meat and spices.

Food irradiation kills bacteria, insects and parasites that can cause food-borne diseases, such as salmonella, trichinosis and cholera. According to the U.S. Department of Agriculture, more than 76 million Americans are affected by food-borne illnesses each year, and more than 5,000 die. In addition to killing bacteria, irradiation can retard spoilage and increase the shelf life of food.

Following an outbreak of illness traced to contaminated salad greens, the FDA in 2008 issued a final rule approving irradiation of iceberg lettuce and spinach. The purpose was to help protect consumers from infection by such bacteria as salmonella and E. coli, the FDA said. The foods affected by the rule are loose, fresh iceberg lettuce and spinach and bagged iceberg lettuce and spinach. The FDA previously had approved irradiation of these foods to kill insects and delay spoilage. However, the doses needed for those purposes are too low to destroy most disease-causing bacteria.

The irradiation process exposes food to gamma rays from cobalt-60, a radioisotope of cobalt. Sometimes, the process uses electron beams or X-rays to produce the gamma rays.

Food irradiation does not make the food radioactive, and it does not change the food any more than canning or freezing.